dart2js cps: Always use interceptors and type tags for 'is' checks.

tests/compiler/dart2js_extra/dart2js_extra.status

Index: tests/compiler/dart2js_extra/dart2js_extra.status
diff --git a/tests/compiler/dart2js_extra/dart2js_extra.status b/tests/compiler/dart2js_extra/dart2js_extra.status
index 5566d8eb4d409e068a7a155c283399b3a9d93afe..7ee71282ab169f6f6a31f298c49b0513a002bce3 100644
--- a/tests/compiler/dart2js_extra/dart2js_extra.status
+++ b/tests/compiler/dart2js_extra/dart2js_extra.status
@@ -65,7 +65,6 @@ deferred_fail_and_retry_worker_test: SkipByDesign # Uses eval to simulate failed
 10216a_test: Crash # Instance of 'TypeOperator': type casts not implemented.
 10216b_test: Crash # Instance of 'TypeOperator': type casts not implemented.
 12320_test: Crash #  Unhandled node
-16407_test: Crash # unsupported element kind: foo:field
 17094_test: RuntimeError # Please triage this failure.
 21666_test: Crash # Instance of 'TypeOperator': type check unimplemented for fInt.
 22868_test: Crash #  cannot handle async/sync*/async* functions
@@ -128,3 +127,4 @@ type_constant_switch_test/none: Crash # (switch (v){}): Unhandled node
 typevariable_factory_test: Crash # Instance of 'TypeOperator': type check unimplemented for A<T>.
 typevariable_substitution_test: Crash # Instance of 'TypeOperator': type check unimplemented for A<T>.
 while_test: Timeout # Please triage this failure.
+16407_test : Pass